In an internal pressure tapping type pressure regulator, a pressure tapping passage is typically in communication with a valve body and the downstream of an actuator, since downstream pressure needs to be directly tapped in the pressure regulator. FIG. 1 is a schematic diagram of a conventional pressure regulating valve with a straight-through type internal pressure tapping structure and FIG. 2 depicts the straight-through type internal pressure tapping structure in greater detail. In FIG. 1 and FIG. 2, an internal pressure tapping passage 12 is a passage through which downstream gas enters a lower chamber of the actuator to sense downstream pressure. FIG. 7 illustrates a curve 1 that represents a performance curve of the straight-through type internal pressure tapping structure shown in FIGS. 1 and 2. From the curve 1, it can be seen that the performance of the pressure regulator in a flow accuracy range is very poor and pressure drop is too fast.